1. Field of the Invention
The present invention relates to an image processing apparatus such as a MPF (Multi Function Peripheral) that is a multifunctional digital machine, an image processing method implemented by this image processing apparatus, a computer readable recording medium having an image processing program stored therein to make a computer of the image processing apparatus execute image processing.
2. Description of the Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
With the development of digital circumstances, which is represented by the recent wide spread of personal computers, false documents can be created easier than before. Furthermore, since the copy quality of copiers has been notably improved, there happens a problem for example, that a copy is made from an original document and some of the sheets are replaced with false ones, and the copy including the false sheets is maliciously distributed as an original document. To cope with such a problem, it is required to ensure the authenticity of an original document.
To prevent illegal document copying, there is an art conventionally suggested by Japanese Unexamined Laid-open Patent Publication No. 2007-116588, in which a copy operation is prohibited if a particular image is included in any side of a sheet having images on its both sides.
However, the art disclosed in the publication above is intended only to prohibit a copy operation if a particular image is included in any side of a sheet having images on its both sides, and not intended to check the authenticity of the sheet. Therefore, this art is not effective to prevent a problem, for example, that a false document is maliciously distributed as an original document.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.